Trocars are surgical instruments that have found wide application in many types of operations where puncture-type incisions are to be made. Early configurations were in the form of sharp pointed stylets or obturators closely surrounded by a hollow trocar tube. The sharp point of the stylet normally extends a short distance from the distal end of the trocar tube when the trocar is in its assembled condition. After thrusting through the body wall into a body cavity, the surgeon uses skill to avoid damaging body tissue and body organs. This type of simple trocar is still widely used.
More recently, improved trocars with means for protecting body organs from unintended incidental damage have been devised. Two such improved trocars are shown in U.S. Pat. No. 4,601,710 to Moll and U.S. Pat. No. 4,654,030 to Moll, et al. With these improved devices, the surrounding trocar tube is forced back against a biasing spring by the action of the obturator tip passing through body wall tissue, so as to expose the stylet point. After passing through the body wall, the protective trocar tube returns to its normal position covering the point, thereby protecting against patient organ damage.
While the prior art trocars are very useful, there are some features that are missing, creating problems. One is the lack of versatility in that the forward trocar tube body cannot be used with simple trocar obturators. Another is the lack of adaptability of the trocar tube main seal to various sizes of surgical instruments while maintaining the sealing effect. Still another is the lack of ability to fully accommodate angulation of the surgical instruments while maintaining the sealing effect.